Game theory and other rational-choice approaches are used frequently in political
science. However, political science research considers political processes in
more detail and their findings complement the results presented above, at least
on three major issues. Although these extensions have important implications
for the conclusions here, the basic insights remain the same.

While game theory analysis usually models states as unitary actors, much political
science research conceives of states as complex political systems. The behaviour
of a complex actor can be seen as a function of three main determinants: the
internal configuration of preferences, the internal distribution of influence
and power, and the nature of political institutions (which specify the decision
rules). Domestic decision-making processes often produce outcomes that differ
significantly from those that maximize the net national welfare. Particularly
relevant in this context are three findings that illustrate systematic biases.

First, in baseline circumstances, the measures that are most easily
adopted and implemented are those that offer tangible benefits to a specific
sector of the economy or organized segments of society, while costs are widely
dispersed throughout society (Underdal, 1998). For most conventional environmental-protection
measures, costs are concentrated while benefits are indeterminate or widely
dispersed, which indicates thatunless the issue really mobilizes the general
publicthe odds favour opponents to the measures, particularly in the implementation
phase.

Second, (environmental) damage that hits the social centre of society
tends to generate more political energy than damage that affects the social
periphery only. This bias is stronger the more skewed the distribution of economic
and political resources. This suggests, for example, that damage suffered primarily
by poor farming communities in developing countries generates a less vigorous
political response than damage that hits the infrastructure of the modern
sectors of the economy (e.g., as a consequence of extreme weather events).

Third, domestic political processes often generate political friction
that limits the scope for international package deals and compensatory arrangements.
Only compensation that benefits the domestic actor(s) who are blocking a particular
solutionor more powerful actorswill be fully effective. Only a subset
of the compensatory arrangements that make sense in terms of economic criteria
will pass the test of political feasibility. These issues of national DMFs are
explored in Section 10.1.

Most of the research reviewed above examines climate change policy in isolation,
on its own merits only. In the real world, new issues enter a policy space that
is already crowded by other problems competing for attention. In such an environment,
the priority given to a particular issue and the chances that a particular option
will be adopted depend on how well it combines with other salient concerns.
As we have seen in, for example, the acid rain case, policy confluence and synergy
can make a significant difference for some of the parties. However, although
the causal mechanism itself is well understood, it is triggered by circumstances
that occur more or less at random. Thus, the aggregate net impact in terms of
the climate change regime cannot be predicted (even if issue linkage, as seen
above, may be a powerful strategy).

The conventional assumption in game theory analysis is that each party aims
to maximize its own welfare, definedwhen dealing with environmental problemsin
terms of damage and abatement costs. Political science research modifies this
assumption in three different directions.